Robust Fault Tolerant Control of Dynamic Positioning Ships based on Typical Actuator Constraints

Abstract

In this paper, a fault-tolerant control method of dynamic positioning(DP) ship under time-varying external disturbance and actuator faults is proposed. A general fault model is established to describe the typical actuator faults modes (loss-of-effectiveness, jamming and interruption). Without using the speed acceleration, a finite time nonlinear disturbance observer is designed to estimate time-varying bounded disturbance and compensate fault error. Then a nonlinear PD fault-tolerant control law is developed, which can guarantee finite time uniform boundedness of all states of the closed-loop system. The effectiveness of the fault-tolerant control method is verified by simulation of "Offshore Oil 201" dynamic positioning ship.